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Discussion Starter · #1 ·
88 Jimmy 2.8 TBI

I STILL have low oil pressure. The gauge is at about 5 at idle and the check gauges light is on. When I give it gas it will come up to about 15-20 and the light goes off, release the gas and it goes back to 5. The thing is if its a cold start the oil pressure will be normal then after running a while it goes down... I replaced the oil presure switch (gauge) and the oil pump. I have no idea where to look. It will drive and runs ok but I dont want to do any damage. Please help me I am lost.

I did notice on the drivers side by the oil filter and the oil pressure switch there is a hole that looks like some kind of unit should be screwed in and there is a plug for it but there was never anything in it so I ignored it. Anyone know what that is. Its below the oil pressure switch.

Thank
 

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How many miles on the engine? Could be a bearing going,if so you want to replace it before damage is done to the crankshaft journal,if not already.
 

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musical engine builder
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throw some 10w 40 or 15w 40 in it and you'll be fine. that's what i'm doing. my truck was worse it would stall cause the oil psi switch would kill the fuel pump cause my psi would drop to zero.
 

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What oil weight too? Should be 10W or 5W 30. If you replaced the oil pump and everything is still normal in the engine then there should not be any reason for low pressure. So I think the milage may be getting the best of it.
 

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Discussion Starter · #5 ·
thanks for the info guys. I have replaced the bearings in it. I just did a complete rebuild and the journals were fine. I have been using high mileage oil 5w-30. i will try sime thicker stuff. One thing is that the camshaft slides into the block but there is nothing to hold it in place except the timing chain and the plate on the opposite side, is there supposed to be a clip in there to keep it from moving back and forth. The timing cover keeps it in place enough but maybe that is where my problem is.

I will try some thicker oil today.
When it runs for a while it obviously has a problem because the u can start to hear some knocking. cold start it and it sounds beautiful.

thanks again
 

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Pushrod for life!
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the plug is there so you can hook up an aftermarket pressure gauge. that is what you should do cause even of the sending unit is new the guage itself might be bad or bad wiring
 

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Jimmy88 said:
thanks for the info guys. I have replaced the bearings in it. I just did a complete rebuild and the journals were fine. I have been using high mileage oil 5w-30. i will try sime thicker stuff. One thing is that the camshaft slides into the block but there is nothing to hold it in place except the timing chain and the plate on the opposite side, is there supposed to be a clip in there to keep it from moving back and forth. The timing cover keeps it in place enough but maybe that is where my problem is.

I will try some thicker oil today.
When it runs for a while it obviously has a problem because the u can start to hear some knocking. cold start it and it sounds beautiful.

thanks again

The lifters make the cam move back in the block and the thrust surface on the back of the timing gear rides on the block.

I dont recommend band-aiding an oiling pressure problem with thicker oil. You should have 10 PSI for every 1000 RPM. At 500RPM you should be getting 10 and you dont want to be much lower. Check with a mechanical guage.
 

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we flew 25 feet
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my truck just graduated 120k like a month ago, and i have the same noise. it used to cold start beautifully but now it taps and clanks and knocks all the time. im thinking it would be more cost effective to get a new motor thrown in there. good idea?
 
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